Plug-in air freshener



FIG. 1 is a perspective view of a plug-in air freshener showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a right view thereof; and,

FIG. 7 is a left view thereof. 

The ornamental design for a plug-in air freshener, as shown. 